This parameter
(db_create_file_dest ) define the default location for data files,
control_files etc, if no location for these files is specified at the
time of their creation.

*/

SQL> alter system set
db_create_file_dest='+DG1' scope=spfile;

System altered.

/*

If you set
db_create_online_log_dest_n, controlfile will get created at the location
specified by db_create_online_log_dest. the database does not create a control
file in DB_CREATE_FILE_DEST or in DB_RECOVERY_FILE_DEST

We skipped this step as redo log
creating in diskgroup can be taken care later.

Here we removed the
control_files parameter from spfile. So next time we restore the control
file it will automatically go to +DG1 diskgroup since it is defined in
db_create_file_dest, and the new path will be automatically updated in spfile.